by Gentry Sorenson

At the conclusion of every harvest, farmers decide what type and how much tillage is needed to prepare the seedbed for next year’s crop.

They consider several factors in order to make the best decisions for their farms, such as topography, drainage and field conditions.

No-till, strip tillage, chisel plow and deep rip are tillage practices that we often see in preparation of planting soybeans after farmers harvest the corn crop. Factors such as fuel use, machinery costs and equipment maintenance are also important considerations.

Crop residue

Tillage operations or intensity of tillage should be adjusted based on the amount of crop residue remaining after harvest. Leaving residue on the surface to reduce windblown erosion is important to help hold soil in place. Higher residue tillage operations—such as no-till and strip-till—limit the amount of fine soil particles that can be carried away by wind and water.

Smaller soil particles formed by aggressive tillage can be moved off-target by wind and water. This is a loss for valuable farmland. Fields that have higher slopes can be prone to water erosion and windblown erosion. No-till or strip till may be a good fit for higher slope environments.

Tillage also impacts soil structure, as it breaks soil apart. When soil structure is altered by tillage operations that are repeatedly performed at the same depth, a compacted layer below the area of tillage can be formed. If tillage is reduced, natural soil structure can be preserved, and the soil will be more resistant to erosion from wind or water.

Other benefits of good soil structure include:

Tillage trials

Long-term tillage trials began in 2003 on seven research farms across Iowa to evaluate tillage intensity. Tillage treatments studied in the trials include no-till, strip tillage, chisel plowing, deep-rip, and moldboard plowing. Trial highlights included the following:

Weighing all factors

It’s important to weigh all factors when making decisions on tillage practices. Consider wind and water movement of the soil and soil structure when making decisions.

If you choose to make a change in your tillage practices, have patience. You may need to adjust your management to help the change in tillage practice succeed. Slight changes to fertilization methods or weed-control methods may be needed. For instance, reduced tillage may increase perennial or biannual weed pressure.

Sorenson is a field agronomist for Iowa State University Extension and Outreach.